Electrohydraulic flanged butterfly valve for eccentric metal seal structure, sealing form for metal to metal seal, metal sealing ring can be exchanged to metal seal, stainless steel plate and graphite composite plate sealing ring to metal seal. Hard seal butterfly valve drive form in addition to electric: electric, worm rod transmission, pneumatic and so on. the butterfly plate of multi-layer hard seal gas butterfly valve is installed in the diameter direction of the pipeline. In the butterfly valve body cylindrical channel, disc disc around the axis of rotation, rotation Angle between 0°~90°, rotation to 90°, the valve is fully open state.